Provided is a high-output and/or high-capacity battery module in which a plurality of flat batteries having electrodes led out of exterior members are stacked and electrically connected in series and/or parallel to each other.
One example of flat battery usable in the battery module is a non-aqueous electrolyte secondary battery. The non-aqueous electrolyte secondary battery is a battery in which a stacked electrode assembly is accommodated together with a non-aqueous electrolytic solution between exterior members. The stacked electrode assembly has a positive electrode, a negative electrode and a separator for preventing a short circuit between the positive and negative electrodes. For example, aluminum laminate sheets are usable as the exterior members. Outer peripheral portions of the aluminum laminate sheets are sealed by fusion bonding to form a battery package such that the stacked electrode assembly can be accommodated in the battery package.
There is known a technique for fusion bonding an outer peripheral portion of the separator with the seal portions of the aluminum laminate sheets in order to prevent a displacement of the stacked electrode assembly in the secondary battery (see Patent Document 1).